Angular2 Design Pattern - Constructing Prepopulated Forms: data down or events up?

Using Angular2 best practices, I'm wondering what the recommended solution is to the following scenario:

I have a form component, which itself is composed of many child components. Sometimes the component-tree is multiple levels deep (e.g.: top-level form component -> birth information component -> birthDate component.) When loaded, the form needs to be pre-populated with existing data. Many of the input fields have validators on them. The data comes from a restful service (using @angular/Http + RXJS).

When I first started the project, I read about how in Angular 2 (and really, even 1.5) encourages data to flow down and events, up. At the time, the top-level component was pulling in the data that I needed for pre-population. So obviously, I said "Aha! Data, down; events, up.... I have the data at the top, so I'll just construct the form using a form-builder at the top level component and pass down the formControl/formGroup object to the child components.

Now that I've thought more in-depth about it, there are clearly different options on how to properly construct this form. Below I've listed the 3 I can easily think of. I'm wondering which of these is the recommended approach. Feel free to add other design options I haven't listed or comment if the question is 100% situational.

1. Construct the FormGroup at the top-level component and down the proper FormControls/AbstractControls to each of the child components.
   • Pro(s): 1) Clear source for where the data is coming from. 2) Questions like validity/pristineness of the form as a whole are easy to check by just looking at the top-level formControl.
   • Con(s): 1) The child components cannot be exported/used on their own. They only make sense/can be pre-populated in the context of their parent, which pulls in the data from a restful service. 2) The source-code for constructing the top level component is really big.

2. Still pull the data in at the top-level component, but construct the controls at the child components.

   • Pro(s): 1) Clear source for where the data is coming from. 2) Model-driven validation rules can move the the child components.
   • Con(s): 1) The child components cannot be exported/used on their own. They only make sense/can be pre-populated in the context of their parent, which pulls in the data from a restful service.

3. Have each child component subscribe to the results from a top-level restful service call and each child constructs their own formControl/component when onNext/onComplete fires for of that subscription.

   • Pro(s): 1) The child components can be exported/used on their own. 2) The source-code for constructing the top-level component is now MUUUUCH smaller - it has been delegated to its children.
   • Con(s): 1) No clean source for where the daa is coming from.

As context for my specific situation, the controller for the current top-level component is ~600 lines of code right now. This is mostly due to constructing the FormGroup with all the validations, etc. at the top level.

Thanks very much for your thoughts!!!